1. Field
The following description relates to a data transmission technique for use in a separate-type base station that uses both wavelength-division multiplexing (WDM) and time-division multiplexing (TDM).
2. Description of the Related Art
Since the advent of smart phones in the market, wireless data traffic has been expected to at least double every year due to the use of a variety of applications, and domestic and international communication providers have long discussed the future evolution of network technologies capable of reducing costs and making efficient use of communication system resources.
Typical wireless networks are equipped with various software and base stations, including hardware equipment for providing various services such as, for example, High-Speed Packet Access (HSPA), Code Division Multiple Access (CDMA), Worldwide Interoperability for Microwave Access (WiMAX), and the like, and may be inefficient in terms of maintenance and operation. To address this problem, a digital unit and a radio unit that are generally installed together in a mobile communication base station may be separated from each other, the digital unit may be installed in a telephone office, and only the radio unit may be installed in the mobile communication base station.
Since the digital unit and the radio unit are connected in a point-to-point manner and the digital unit and the radio unit transmit data using the same medium, it may be difficult to perform multiplexing. In addition, the digital unit and the radio unit may use the same wavelengths. In a case in which the digital unit is hierachized, the transmission speed of the digital unit may be considerably affected by the degree of hierarchization of the digital unit. Moreover, since the transmission of data via the radio unit is affected by a minimum amount of time required for synchronization, the radio unit may have a limited transmission distance.